This invention relates to compounds having pharmacological activity, processes for their preparation, to compositions containing them and to their use in the treatment of CNS disorders.
EPA 0 021 580 and EPA 0 076 072 describe sulphonamide derivatives which are disclosed as having antiarrhythmic activity. A structurally distinct class of compounds has now been discovered, which have been found to have 5HT6 receptor antagonist activity. 5HT6 receptor antagonists are believed to be of potential use in the treatment of certain CNS disorders such as anxiety, depression, epilepsy, obsessive compulsive disorders, migraine, cognitive memory enhancement e.g. for the treatment Alzheimers disease, sleep disorders, feeding disorders such as anorexia and bulimia, panic attacks, withdrawal from drug abuse such as cocaine, ethanol, nicotine and benzodiazepines, schizophrenia, and also disorders associated with spinal trauma and/or head injury such as hydrocephalus. Compounds of the invention are also expected to be of use in the treatment of certain GI (gastrointestinal) disorders such as IBS (Irritable Bowel Syndrome).
The present invention therefore provides, in a first aspect, a compound of formula (I) or a salt thereof: 
wherein:
P is phenyl, naphthyl, a bicyclic heterocyclic ring or is a 5 to 7-membered heterocyclic ring each containing 1 to 4 heteroatoms selected from oxygen, nitrogen or sulphur;
A is a single bond, a C1-6alkylene or a C1-6alkenylene group;
R1 is halogen, C1-6alkyl optionally substituted by one or more halogen atoms, C3-6cycloalkyl, COC1-6alkyl, C1-6alkoxy, OCF3, hydroxy, hydroxyC1-6alkyl, hydroxyC1-6alkoxy, C1-6alkoxyC1-6alkoxy, C1-6alkanoyl, nitro, amino, C1-6alkylamino or diC1-6alkylamino, cyano or R1 is phenyl, naphthyl, a bicyclic heterocyclic ring or is a 5 to 7-membered heterocyclic ring each containing 1 to 4 heteroatoms selected from oxygen, nitrogen or sulphur;
n is 0, 1, 2, 3, 4, 5 or 6,
R2 is hydrogen, C1-6 alkyl or aryl C1-6 alkyl;
R3 is a group R5 or together with R5 forms a group (CH2)2O or (CH2)3O or R3 is linked to R2 to form a group (CH2)2 or (CH2)3;
R4 is xe2x80x94X(CH2)pxe2x80x94R6 where X is a single bond, CH2, O, NH or Nxe2x80x94C1-6 alkyl and p is 0 to 6 and R6 is an optionally substituted 5- to 7-membered heterocyclic ring containing 1 to 3 heteroatoms selected from nitrogen, sulphur or oxygen, or R6 is NR7R8 where R7 and R8 are independently hydrogen, C1-6 alkyl or aryl C1-6 alkyl; and
R5 is hydrogen, halogen, C1-6alkyl, C3-6cycloalkyl, COC1-6alkyl, C1-6alkoxy, hydroxy, hydroxyC1-6alkyl, hydroxyC1-6alkoxy, C1-6alkoxyC1-6alkoxy, C1-6 alkanoyl, nitro, trifluoromethyl, cyano or aryl.
C1-6Alkyl groups, whether alone or as part of another group, may be straight chain or branched. Preferred alkyl groups are generally methyl and ethyl. As used herein the term aryl includes optionally substituted phenyl and naphthyl.
When P is a bicyclic heterocyclic ring suitable examples include benzothiophene, quinoline or isoquinoline. When P is a 5 to 7-membered heterocyclic ring suitable examples include thienyl, furyl, pyrrolyl, triazolyl, diazolyl, imidazolyl, oxazolyl, thiazolyl, oxadiazolyl, isothiazolyl, isoxazolyl, thiadiazolyl, pyridyl, pyrimidyl, pyrrolidinyl and pyrazinyl. The heterocyclic rings can be linked to the remainder of the molecule via any suitable carbon atom or, when present, a nitrogen atom. Suitable substituents for these rings include R5 groups as defined above.
Preferably P is phenyl, thiophene, benzothiophene or naphthyl. Preferably A is a single bond, an ethylene group or a xe2x80x94CHxe2x95x90CHxe2x80x94 group. Most preferably A is a single bond.
When R1 is a heterocyclic group suitable examples include those listed above. Preferably R1 is halogen or C1-6alkyl optionally substituted by one or more halogen atoms, for example methyl or trifluoromethyl.
Preferably n is 0, 1, 2 or 3, particularly 1 or 2.
Suitably R2 is hydrogen or C1-6 alkyl. Preferably R2 is hydrogen.
It will be appreciated that when R3/R5 groups are linked together the two groups must be attached to adjacent carbon atoms of the phenyl ring. Preferably R3 is a group R5, in particular hydrogen.
Preferably R4 is meta with respect to the sulphonamide linkage. Preferably X is a bond, p is 0 and R6 is an optionally substituted 5- to 7-membered heterocyclic ring. The heterocyclic rings can be linked to the remainder of the molecule via a carbon atom or, when present, a nitrogen atom. Optional substituents for these rings, which can be present on carbon and/or nitrogen atoms, include C1-6alkyl, in particular methyl. More preferably R4 is N-piperazine optionally substituted by C1-6alkyl, particularly unsubstituted piperazine.
Preferably R5 is C1-6alkoxy, most preferably methoxy. Preferably R5 is para with respect to the sulphonamide linkage.
A preferred meaning for P-A is benzo[b]thiophen-2-yl or benzo[b]thiophen-3-yl optionally substituted by one or two R1 groups, especially 5-chloro-3-methylbenzo[2]thiophen-2-yl.
Particular compounds of the invention include:
4-Bromo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-thiophenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-5-(pyridin-2-yl)-2-thiophenesulfonamide,
2,5-Dichloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-3-thiophenesulfonamide,
4-Bromo-5-chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-thiophenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
3-Bromo-5-chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-thiophenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzylsulfonamide,
2-Bromo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
3-Bromo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
3-Chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-4-methylbenzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-trans-styrenesulfonamide,
3,4-Dichloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
3,5-Dichloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-[2,1,3]benzothiadiazole-4-sulfonamide,
5-Chloro-N-[4methoxy-3-(4-methylpiperazin-1-yl)phenyl]-3-methyl-2-benzothiophenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-methyl-5-nitrobenzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-trifluoromethylbenzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-3-trifluoromethylbenzenesulfonamide,
2,5-Dimethoxy-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-benzenesulfonamide,
4-Fluoro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-Chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-Iodo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-Ethyl-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-tert-Butyl-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-Isopropyl-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-tert-Amyl-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-4-trifluoromethoxybenzenesulfonamide,
4-n-Butoxy-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-4-methylbenzenesulfonamide,
5-Chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-thiophenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-1-naphthalenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-naphthalenesulfonamide,
5-(Dimethylamino)-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-1-naphthalenesulfonamide,
4-Bromo-N-[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]-benzenesulfonamide,
4-Methoxy-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-n-Butyl-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-Amino-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
2-Chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
3-Chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
2,3,4-Trichloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-benzenesulfonamide,
4-Chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2,5-dimethylbenzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-3-methylbenzenesulfonamide,
2,5-Dibromo-3,6-difluoro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-benzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2,3,5,6-tetramethylbenzenesulfonamide,
5-Chloro-2-methoxy-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-benzenesulfonamide,
3-Fluoro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
3,4-Difluoro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
4-Chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-3-nitrobenzenesulfonamide,
3-Chloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-methylbenzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-8-quinolinesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-4-phenylbenzenesulfonamide,
3,4-Dimethoxy-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-benzenesulfonamide,
N-[4-Methoxy-3-(4-methylpiperazin-1-yl)phenyl]-3,5-dimethyl-4-isoxazolesulfonamide,
4-Bromo-N-[4-methoxy-3-(4-ethylpiperazin-1-yl)phenyl]benzenesulfonamide,
2,3-Dichloro-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-benzenesulfonamide,
5-Iodo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2-methylbenzenesulfonamide,
3-Iodo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide,
3-Iodo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-4-methylbenzenesulfonamide,
5-Chloronaphthalene-2-sulfonic acid[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide,
5-Chloronaphthalene-1-sulfonic acid[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide,
4-Chloronaphthalene-1-sulfonic acid[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide,
7-Chloronaphthalene-1-sulfonic acid[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide,
5-Chloro-2-methylbenzo[b]thiophene-3-sulfonic acid[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide,
Benzofuran-2-sulfonic acid[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide,
1-Methyl-1H-indole-2-sulfonic acid[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide,
5-Pyridin-2-ylthiophene-2-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
N-(4-Methoxy-3-piperazin-1-ylphenyl)-3-trifluoromethylbenzenesulfonamide,
3-Iodo-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
3,5-Dimethylisoxazole-4-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
3,5-Dichloro-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
2,5-Dibromo-3,6-difluoro-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
Naphthalene-1-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
2-Bromo-5-chlorothiophene-2-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
2-Chloro4-fluoro-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
3-Bromo-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
3-Chloro-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
5-Chloronaphthalene-2-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
4-Bromo-5-chlorothiophene-2-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
2,5-Dichlorothiophene-3-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide
4-Bromo-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
5-Chloro-2-methylbenzo[b]thiophene-3-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
1-Methyl-1H-indole-2-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
Benzofuran-2-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
Naphthalene-2-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
5-Chloronaphthalene-1-sulfonic acid(4-methoxy-3-piperazin-1-ylphenyl)amide,
4-Chloro-2,5-dimethyl-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
3,4-Dichloro-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
3-Chloro-N-(4-methoxy-3-piperazin-1-ylphenyl)-4-methylbenzenesulfonamide,
2-Trifluoromethyl-N-(4-methoxy-3-piperazin-1ylphenyl)benzenesulfonamide,
4-Iodo-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
4-tert-Butyl-N-(4-methoxy-3-piperazin-1-ylphenyl)benzenesulfonamide,
Naphthalene-1-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide,
Thiophene-2-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide,
5-Chlorothiophene-2-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide,
5-Pyridin-2-ylthiophene-2-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide,
2,5-Dichlorothiophene-3-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide,
4-Bromo-5-chlorothiophene-2-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide,
3-Bromo-5-chlorothiophene-2-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide,
4-Chloro-2,5-dimethyl-N-[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]benzenesulfonamide,
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide,
Naphthalene-2-sulfonic acid[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]amide.
3-Bromo-N-[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]benzenesulfonamide,
3,5-Dichloro-N-[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]benzenesulfonamide,
4-tert-Butyl-N-[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]benzenesulfonamide,
2,5-Dibromo-3,6-difluoro-N-[7-(4-methylpiperazin-1-yl)-2,3-dihydrobenzofuran-5-yl]benzenesulfonamide,
2,5-Dibromo-3,6-difluoro-N-(7-piperazin-1-yl-2,3-dihydrobenzofuran-5-yl)benzenesulfonamide,
4-Chloro-2,5-dimethyl-N-(7-piperazin-1-yl-2,3-dihydrobenzofuran-5-yl)benzenesulfonamide,
5-Chloro-3-methyl benzo[b]thiophene-2-sulphonic acid[3-(4-cyclopropylmethylpiperazin-1-yl)-4-methoxy-phenyl]amide,
5-Chloro-3-methyl benzo[b]thiophene-2-sulphonic acid[3-(4-benzylpiperazin-1-yl)-4-methoxy-phenyl]-amide,
5-Chloro-3-methyl-benzo[b]thiophene-2-sulphonic acid[4-hydroxy-3-(4-methylpiperazin-1-yl)-phenyl]-amide,
5-Chloro-3-methyl-benzo[b]thiophene-2-sulphonic acid[4-benzyloxy-3-(4-methylpiperazin-1-yl)-phenyl]-amide,
5-Chloro-3-methyl-benzo[b]thiophene-2-sulphonic acid[4-ethoxy-3-(4-methylpiperazin-1-yl)-phenyl]-amide,
5-Chloro-3-methyl-benzo[b]thiophene-2-sulphonic acid[4-isopropoxy-3-(4-methylpiperazin-1-yl)-phenyl]-amide,
5-Chloro-3-methyl-benzo[b]thiophene-2-sulphonic acid[4-methoxy-3-(1-methylpyrrolidin-3-yloxy)-phenyl]-amide,
Naphthalene-2-sulfonic acid[2-bromo-5-(4-methylpiperazin-1-yl)phenyl]amide
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[4-chloro-3-(4-methylpiperazin-1-yl)phenyl]amide,
Naphthalene-2-sulfonic acid[4-bromo-3-(4-methylpiperazin-1-yl)phenyl]amide,
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[3-(2-dimethylaminoethoxy)-4-iodophenyl]amide,
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[1-(2-dimethylaminoethyl)-2,3-dihydro-1H-indol-6-yl]amide,
1-(5-Chloro-3-methylbenzo[b]thiophene-2-sulfonyl)-6-(4-methylpiperazin-1-yl)-2,3-dihydro-1H-indole,
1-(5-Chloro-3-methylbenzo[b]thiophene-2-sulfonyl)-5-methoxy-6-(4-methylpiperazin-1-yl)-2,3-dihydro-1H-indole
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[4-methoxy-2-methyl-3-(4-methylpiperazin-1-yl)phenyl]amide,
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[2-(2-hydroxyethyl)-4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide,
1-(5-Chloro-3-methylbenzo[b]thiophene-2-sulfonyl)-5-methoxy-4-(4-methylpiperazin-1-yl)-2,3-dihydro-1H-indole hydrochloride,
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[3-methoxy-4-(4-methylpiperazin-1-yl)phenyl]amide,
4-Bromo-N-[4-methoxy-3-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)phenyl]benzenesulfonamide,
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[4-methoxy-3-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)phenyl]amide
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid[4-methoxy-3-(1-methylpiperidinyl)phenyl]amide
Naphthalene-2-sulfonic acid[3-(4-methylpiperazin-1-yl)phenyl]amide and pharmaceutically acceptable salts thereof
The compounds of the formula (I) can form acid addition salts with acids, such as conventional pharmaceutically acceptable acids, for example maleic, hydrochloric, hydrobromic, phosphoric, acetic, fumaric, salicylic, citric, lactic, mandelic, tartaric and methanesulphonic.
Compounds of formula (I) may also form solvates such as hydrates, and the invention also extends to these forms. When referred to herein, it is understood that the term xe2x80x98compound of formula (I)xe2x80x99 also includes these forms.
Certain compounds of formula (I) are capable of existing in stereoisomeric forms including diastereomers and enantiomers and the invention extends to each of these stereoisomeric forms and to mixtures thereof including racemates. The different stereoisomeric forms may be separated one from the other by the usual methods, or any given isomer may be obtained by stereospecific or asymmetric synthesis. The invention also extends to any tautomeric forms and mixtures thereof.
The present invention also provides a process for the preparation of a compound of formula (I) or a pharmaceutically acceptable salt thereof, which process comprises the coupling of a compound of formula (II): 
in which R1, n, P, and A are as defined in formula (I) or protected derivatives thereof and L is a leaving group with a compound of formula (III): 
in which R2, R3, R4 and R5 are as defined in formula (I) or protected derivatives thereof and optionally thereafter:
removing any protecting groups,
forming a pharmaceutically acceptable salt.
Suitable leaving groups include halogen, in particular chloro. The reaction of a compounds of formulae (II) and (III) is carried out by mixing the two reagents together, optionally in an inert solvent such as acetone. Such a reaction may be carried out in the presence of base.
Those skilled in the art will appreciate that it may be necesary to protect certain groups. Suitable protecting groups and methods for their attachment and removal are conventional in the art of organic chemistry, such as those described in Greene T. W. xe2x80x98Protective groups in organic synthesisxe2x80x99 New York, Wiley (1981). For example, suitable protecting groups for the piperazine group include BOC, COCCl3, COCF3 and methyl the latter of which may be removed by treatment with 1-chloroethyl chloroformate according to standard procedures.
N-substituted piperazines can be prepared by acylation or alkylation of the appropriate NH-piperazine compound according to standard procedures.
Compounds of formulae (II) and (III) are commercially available or may be prepared according to known methods or analogous to known methods.
Pharmaceutically acceptable salts may be prepared conventionally by reaction with the appropriate acid or acid derivative.
Compounds of formula (I) and their pharmaceutically acceptable salts have 5HT6 receptor antagonist activity and are believed to be of potential use in the treatment of certain CNS disorders such as anxiety, depression, epilepsy, obsessive compulsive disorders, migraine, Alzheimers disease (cognitive memory enhancement), sleep disorders (including disturbances of Circadian Rythym), feeding disorders such as anorexia and bulimia, panic attacks, withdrawal from drug abuse such as cocaine, ethanol, nicotine and benzodiazepines, schizophrenia, and also disorders associated with spinal trauma and/or head injury such as hydrocephalus. Compounds of the invention are also expected to be of use in the treatment of certain GI disorders such as IBS
Thus the invention also provides a compound of formula (I) or a pharmaceutically acceptable salt thereof, for use as a therapeutic substance, in particular in the treatment or prophylaxis of the above disorders.
The invention further provides a method of treatment or prophylaxis of the above disorders, in mammals including humans, which comprises administering to the sufferer a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.
In another aspect, the invention provides the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for the treatment or prophylaxis of the above disorders.
The present invention also provides a pharmaceutical composition, which comprises a compound of formula (I) or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.
A pharmaceutical composition of the invention, which may be prepared by admixture, suitably at ambient temperature and atmospheric pressure, is usually adapted for oral, parenteral or rectal administration and, as such, may be in the form of tablets, capsules, oral liquid preparations, powders, granules, lozenges, reconstitutable powders, injectable or infusable solutions or suspensions or suppositories. Orally administrable compositions are generally preferred.
Tablets and capsules for oral administration may be in unit dose form, and may contain conventional excipients, such as binding agents, fillers, tabletting lubricants, disintegrants and acceptable wetting agents. The tablets may be coated according to methods well known in normal pharmaceutical practice.
Oral liquid preparations may be in the form of, for example, aqueous or oily suspension, solutions, emulsions, syrups or elixirs, or may be in the form of a dry product for reconstitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, emulsifying agents, non-aqueous vehicles (which may include edible oils), preservatives, and, if desired, conventional flavourings or colourants.
For parenteral administration, fluid unit dosage forms are prepared utilising a compound of the invention or pharmaceutically acceptable salt thereof and a sterile vehicle. The compound, depending on the vehicle and concentration used, can be either suspended or dissolved in the vehicle. In preparing solutions, the compound can be dissolved for injection and filter sterilised before filling into a suitable vial or ampoule and sealing. Advantageously, adjuvants such as a local anaesthetic, preservatives and buffering agents are dissolved in the vehicle. To enhance the stability, the composition can be frozen after filling into the vial and the water removed under vacuum. Parenteral suspensions are prepared in substantially the same manner, except that the compound is suspended in the vehicle instead of being dissolved, and sterilization cannot be accomplished by filtration. The compound can be sterilised by exposure to ethylene oxide before suspension in a sterile vehicle. Advantageously, a surfactant or wetting agent is included in the composition to facilitate uniform distribution of the compound.
The composition may contain from 0.1% to 99% by weight, preferably from 10 to 60% by weight, of the active material, depending on the method of administration.
The dose of the compound used in the treatment of the aforementioned disorders will vary in the usual way with the seriousness of the disorders, the weight of the sufferer, and other similar factors. However, as a general guide suitable unit doses may be 0.05 to 1000 mg, more suitably 0.05 to 20.0 mg, for example 0.2 to 5 mg; and such unit doses may be administered more than once a day, for example two or three a day, so that the total daily dosage is in the range of about 0.5 to 100 mg; and such therapy may extend for a number of weeks or months.
When administered in accordance with the invention, no unacceptable toxicological effects are expected with the compounds of the invention.
The following Descriptions and Examples illustrate the preparation of compounds of the invention.
A solution of 5M sulphuric acid (114 ml) was added over 0.3 h to 1-(2-methoxyphenyl)piperazine (110 g) at 0xc2x0 C. with stirring. To the ice-cooled stirred slurry was then added, over 1.75 h, concentrated sulphuric acid (560 ml) and the temperature was maintained for a further 1.5 h. Potassium nitrate (71.5 g) was then added portionwise over 1.5 h to the stirred, cold, viscous mixture which was then left to stand for 18 h. The solution was poured onto ice (2 Kg) and the resulting cooled mixture brought to pH 12 by the addition of 40% sodium hydroxide solution. The oily mixture was extracted with ethyl acetate (2xc3x972L) and the combined organic extracts were washed with water (3L), dried (Na2SO4), concentrated to a residue which was stirred with diethyl ether (700 ml) to give the title compound (D1) as a yellow solid, m.p. 84-87xc2x0 C. (95 g, 70%). MH+238.
To a stirred heterogeneous solution of 1-(2-methoxy-5-nitrophenyl)piperazine (D1) (99.2 g) in tetrahydrofuran (1.1L) and water (1.1L) was added a solution of di-tert-butyldicarbonate (91.3 g) in tetrahydrofuran (300 ml) over 0.5 h. Potassium carbonate (60.7 g) was then added in portions over 0.5 h and the mixture was stirred at ambient temperature for 18 h. The whole was concentrated to remove the organic solvent and the resulting mixture was extracted with dichloromethane (2xc3x971L). The combined organic phases were washed with water (1L), dried (Na2SO4) and concentrated to a residue which was stirred with diethyl ether (500 ml) and hexane (750 ml) to afford the title compound (D2)as a yellow solid, m.p. 136-7xc2x0 C. (125 g, 89%). MH+338.
A slurry of 10% palladium on carbon (10 g) in a solution of 4-tert-butoxycarbonyl-1-(2-methoxy-5-nitrophenyl)piperazine (D2) (124.5 g) in ethanol (3.5L) and water (50 ml) was stirred with hydrogen at ambient temperature and atmospheric pressure for 18 h. The reaction mixture was filtered and the filtrate concentrated to afford the title compound (D3) as a gum (112 g, 99%). MH+ 308.
A solution of 4t-butoxycarbonyl-1-(5-amino-2-methoxyphenyl)piperazine (D3) (15.6 mmol), diisopropylethylamine (15.6 mmol) and the appropriate aryl sulfonyl chloride (15.6 mmol) in dichloromethane (100 ml) was stirred at room temperature for 18 h. The mixture was concentrated and the residue chromatographed on silica gel eluting with a dichloromethanelmethanol gradient to give the following pure title products.
5-Chloro-3-methylbenzo[b]thiophene-2-sulfonic acid(4-methoxy-3-(4-tert-butoxycarbonylpiperazin-1phenyl)amide (D10)
Pyridine (60 ml) was added to a stirred solution of 4-tert-butoxycarbonyl-1-(5-amino-2-methoxyphenyl)piperazine (D3) (112 g) in dichloromethane (1L) at ambient temperature under argon. To this solution was added over 0.75 h a solution of 5-Chloro-3-methylbenzo[b]thiophene-2-sulfonyl chloride (102.5 g) in dichloromethane (2.1L) and the purple solution was stirred for 18 h. The mixture was then washed with 1M hydrochloric acid solution (3L), water (3L), dried (Na2SO4), and concentrated to a foam which was stirred with acetone (800 ml) and water (800 ml) to afford the title compound (D10) as a maroon solid, m.p. 100-103xc2x0 C. (194.9 g, 97%). MH+ 552/554.
A solution of 5-nitro-1-(2-methoxyphenyl)piperazine (D1) (44 g) in dichloromethane (300 ml) was added to a stirred solution of trichloroacetylchloride (32 ml) in dichloromethane (200 ml) over 0.25 h. After 3 hrs, the reaction mixture was concentrated and the residue recrystallised from chloroform to yield the title compound (D15) as a yellow solid (43 g, 61%). Found MH+ 382/384.
A solution of stannous chloride dihydrate (27 g) in concentrated HCl (60 ml) was slowly added to a stirred suspension of 1-(2-methoxy-5-nitrophenyl)-4-trichloroacetylpiperazine (D15) (15 g) in concentrated HCl/ethanol (1:2, 120 ml). After 24 hrs, the mixture was filtered, diluted with dichloromethane (600 ml) and basified with Na2CO3 solution. The layers were separated, the organic phase dried, concentrated to ⅓ the volume and acidified with 1M ethereal HCl solution to afford the title compound (D16) as a green solid (2.5 g, 15%). Found MH+ 352.
To a solution of 1-(2-methoxy-5-nitrophenyl)-piperazine (500 mg, 2.1 mmol) in dichloromethane (50 ml) at 0xc2x0 C. under argon was added triethylamine (0.59 ml, 4.2 mmol) and cyclopropane carbonyl chloride (2.1 mmol). Stirring was continued for 12 hrs. The reaction mixture was concentrated in vacuo and partitioned between saturated aqueous NaHCO3 and dichloromethane. The organic layer was dried over sodium sulphate and concentrated in vacuo to give the title compound (D17) in 90% yield. Found MH+ 306.
The title compound was prepared in 85% yield using the procedure outlined in D17 using benzoyl chloride. Found MH+342.
A solution of the cyclopropyl-[4-(2-methoxy-5-nitrophenyl)-piperazin-1-yl]methanone (D17) (1.8 mmol) in ethanol was hydrogenated over 10% Palladium on charcoal catalyst for 2 hrs at room temperature to give the title compound in 91% yield. Found MH+ 276.
The title compound was prepared in 95% yield using the procedure outlined in D19. Found MH+ 312
To a solution of [4-(5-amino-2-methoxy-phenyl)-piperazin-1-yl]cyclopropyl methanone (D19) (1.6 mmol) in dry THF (10 ml) under argon was added LiAlH4 (240 mg, 6.4 mmol). The resulting mixture was heated to reflux for 12 hrs and cooled before quenching with water (0.25 ml), 10% aqueous NaOH (0.25 ml) and finally water (0.75 ml). Filtration through celite and concentration in vacuo afforded the title compound (D21) in 75% yield. Found MH+ 262.
The title compound was prepared in 76% yield using the procedure outlined in D21. Found MH+ 298.
To a solution of 1-methyl-pyrrolidin-3-ol (2.0 g, 20 mmol) and triethylamine (3 ml, 22 mmol) in dichloromethane (25 ml) at 0xc2x0 C. under argon was added methane sulphonyl chloride (2.4 g, 21 mmol). Stirring was continued at 0xc2x0 C. to room temperature for 1 hr before partitioning between saturated aqueous sodium bicarbonate and dichloromethane. The organic phase was dried over sodium sulphate and concentrated in vacua to afford the crude mesylate (3.6 g) which was used directly in the next step.
A solution of 2-methoxy-5-nitro phenol (5.1 g, 30 mmol) in DMF (10 ml) was added to sodium hydride (1.6 g, 66 mmol) under argon. After 1 hr a solution of the crude mesylate (D23, 3.6 g, 20 mmol) in DMF (10 ml) was added and the reaction mixture warmed to 50xc2x0 C. for 48 hrs. The reaction was cooled, quenched with water and concentrated in vacuo before partitioning between saturated aqueous sodium bicarbonate and dichloromethane. The organic phase was dried over sodium sulphate and concentrated in vacuo. The residue was purified by chromatography on silica gel to afford the title compound (D24). Found MH+ 253.
A solution of 3-(2-methoxy-5-nitro-phenoxy)-1-methyl-pyrrolidine (3.0 g, 0.12 mmol) in ethanol (50 ml) was hydrogenated over 10% palladium on charcoal catalyst for 2 hrs to afford the title compound (D25). Found MH+ 223.
A solution of 1-methyl-4-(3-nitrophenyl)piperazine (EP0533267A) (1.0 g; 4.5 mmol) in glacial acetic acid (25 ml) was treated with bromine (0.23 ml; 1 equivalent). The reaction mixture was stirred at 75xc2x0 overnight, then cooled, filtered, and the yellow sticky solid was partitioned between potassium carbonate (aq) and 2% methanol in dichloromethane. The organic phase was dried (Na2SO4) and evaporated under reduced pressure to leave the title compound (D26) as a viscous orange oil (928 mg, 68%) MH+=300/302.
A suspension of iron powder (1.77 g, 31.6 mmol) in saturated aqueous ammonium chloride solution (140 ml) at 100xc2x0 C., was treated dropwise with a solution of 1-(4-bromo-3-nitrophenyl)-4-methylpiperazine (D26) (3.54 g, 11.8 mmol) in methanol (70 ml). The mixture was refluxed for a further 1 h, and was then cooled and partitioned between water and 3% methanol in dichloromethane. The organic phase was dried (Na2SO4) and evaporated under reduced pressure to give the crude product. This was purified by chromatography on silica gel, eluting with methanol and dichloromethane to give the title compound (D27) as a white solid (2.18 g, 68%) MH+=270/272.
A solution of 1-methoxy-3-methyl-2-nitrobenzene (15.04 g, 0.09 mol) in ethanol (250 ml) was hydrogenated over 10% palladium on charcoal (4 g) at atmospheric pressure and at room temperature, for 18 h. The catalyst was removed by filtration, and the filtrate evaporated under reduced pressure to leave the title compound (D28) as an amber oil, which crystallised on standing (11.18 g, 91%).
1H NMR (250 MHz, CDCl3) xcex4 (ppm): 6.75-6.65 (m, 3H), 3.81 (s, 3H), 3.72 (br s, 2H), 2.19 (s, 3H).
A mixture of 2-methoxy-6-methylphenylamine (D28) (3.62 g, 26.4 mmol), mechlorethamine hydrochloride (12.7 g, 66 mmol) and potassium carbonate (15 g) in chlorobenzene (90 ml) was refluxed under argon for 20 h. The mixture was cooled and filtered, and the filtrate evaporated under reduced pressure to leave the title compound (D29) as a red oil which slowly crystallised on standing (5.4 g, 93%) MH+=221.
A solution of 1-(2-methoxy-6-methylphenyl)-4-methylpiperazine (D29) (6.2 g, 28 mmol) in concentrated sulfuric acid (50 ml) was treated portionwise with potassium nitrate (3.3 g, 33 mmol) over 5 mins, maintaining the temperature at 25-30xc2x0 C. The mixture was stirred overnight at room temperature, then added to ice, and basified with 40% sodium hydroxide solution. The mixture was extracted with dichloromethane and the organic phase was dried (Na2SO4) and evaporated under reduced pressure to give crude compound. Purification by chromatography on silica gel eluting with methanol and dichloromethane afforded the title compound (D30) (4.56 g, 61%) MH+=266.
A mixture of 1-(6-methoxy-2-methyl-3-nitrophenyl)-4-methylpiperazine (D30) (360 mg, 1.36 mmol), dry dimethylsulfoxide (3 ml), paraformaldehyde (82 mg, 2.72 mmol) and potassium tert-butoxide (52 mg, 0.46 mmol) was heated at 70-75xc2x0 C. for 30 h. After cooling, the mixture was partitioned between water and ethyl acetate. The organic phase was dried (Na2SO4) evaporated under reduced pressure and purified by chromatography on silica gel, eluting with methanol and dichloromethane, to give the title compound (D31) as a yellow solid (152 mg, 38%) MH+=296.
The title compound (D32) was prepared from 2-[3-methoxy-2-(4-methylpiperazin-1-yl)-6-nitrophenyl]ethanol (D31) (142 mg, 0.48 mmol) using the method of Description 28 as a clear oil which crystallised on standing (94 mg, 74%) MH+=266.
The title compound (D33) was prepared from 1-(6-methoxy-2-methyl-3-nitrophenyl)-4-methylpiperazine (D30) (150 mg, 0.56 mmol) using the method of Description 28 as a tan powder (78 mg, 59%) MH+=236.
A mixture of N-methylpiperazine (216 mg, 2.15 mmol), 2-bromo-5-nitroanisole (1 g, 4.3 mmol), potassium carbonate (447 mg, 3.23 mmol), copper (I) bromide (86.6 mg, 0.30 mmol) in pyridine (0.5 ml) and toluene (2 ml) was heated at 100xc2x0 C. overnight. After cooling, the mixture was partitioned between water and ether and the aqueous phase was further extracted with ethyl acetate. The combined organic phases were dried (Na2SO4) and evaporated under reduced pressure, to give the crude product. This was purified by chromatography on silica gel, eluting with methanol and dichloromethane, to give the title compound (D34) as a yellow/brown oil (80 mg, 15%) MH+=252.
The title compound (D35) was prepared from 1-(2-methoxy-4-nitrophenyl)-4-methylpiperazine (D34) (80 mg, 0.319 mmol) using the method of Description 28 (50 mg, 71%) MH+=222.
A stirred mixture of 2-bromo-4-nitroanisole (7.6 g, 32.7 mmol), 4-pyridineboronic acid (4.07 g, 33 mmol) and powdered sodium carbonate (13.8 g, 5 equivalents) in 1:1 1,2-dimethoxyethane:water (1,360 ml) was degassed for 0.5 hr, by the passage of a stream of argon. Tetrakistriphenylphosphine palladium (0) (1.35 g) was added, and the mixture was cooled, the solvents evaporated under reduced pressure to approximately half-volume, and the aqueous residue was acidified with 5N hydrochloric acid and washed with ethyl acetate. The acid phase was then basified with solid potassium carbonate, and extracted into ethyl acetate, the organic phase was dried (Na2SO4) and evaporated under reduced pressure to give the title compound (D36) as a pale yellow solid (3.4 g, 45%).
1H NMR (250 MHz, CDCl3) xcex4 (ppm): 8.7 (d, 2H), 8.32 (d, 1H), 8.29-8.25 (m, 1H), 7.47 (d, 2H), 7.09 (d, 1H), 3.96 (s, 3H).
A solution of 4-(2-methoxy-5-nitrophenyl)pyridine (D36) (3.4 g, 14.8 mmol) in acetone (150 ml) was treated with excess iodomethane (5 ml) and the mixture stirred at room temperature overnight. The precipitated quaternary salt was filtered off, washed with acetone and dried, giving 5.02 g. This was dissolved in 1:1 ethanol:water (230 ml) and treated portionwise at room temperature, under argon, with sodium borohydride (1.23 g, 32.4 mmol). The mixture was stirred for 1 h at room temperature then potassium carbonate (10 g) was added and the organic layer was separated from the aqueous phase, which was back-extracted with ethyl acetate. The organic phases were combined and dried (Na2SO4) and evaporated under reduced pressure to give the title compound (D37) as an orange oil, which slowly crystallised (3.05 g, 91%).
1H NMR (250 MHz, CDCl3) xcex4 (ppm): 8.15 (d, 1H), 8.05 (s, 1H), 6.9 (d, 1H), 5.9-5.84 (m, 1H), 3.9 (s, 3H), 3.15-3.05 (m, 2H), 2.7-2.61 (m, 2H), 2.6-2.5 (m, 2H), 2.4 (s, 3H).
A solution of 4-(2-methoxy-5-nitrophenyl)-1-methyl-1,2,3,6-tetrahydropyridine (D37) (1.0 g, 4 mmol) in ethanol (50 ml) and glacial acetic acid (5 ml) was hydrogenated over 10% palladium on charcoal at 50xc2x0 C. and 50 psi for 4 days. The catalyst was removed by filtration, the filtrate evaporated under reduced pressure and the residue partitioned between potassium carbonate (aq) and dichloromethane. The organic phase was dried (Na2SO4) and evaporated under reduced pressure to give the title compound (D38) as a brown oil which rapidly crystallised to a light tan powder (760 mg, 86%). MH+=221.
A solution of 4-(2-methoxy-5-nitrophenyl)-1-methyl-1,2,3,6-tetrahydropyridine (D37) (570 mg, 2 mmol), in ethanol (35 ml), was warmed to 60xc2x0 C. and treated dropwise with a solution of stannous chloride (2 g) in conc. hydrochloric acid (4 ml). The mixture was heated for a further 2 h after addition, and allowed to cool. The precipitate was filtered off, and washed with ethanol to give the title compound (D39) as a pale yellow powder (580 mg, 99%). MH+=219.
A solution of 1-(2-methoxy-5-nitrophenyl)piperazine (9.7 g) in N-methylpyrrolidin-2-one (NMP) (150 ml) was heated with chloromethylpolystyrene-divinylbenzene resin (Merrifield, 150-300 mesh) at 60xc2x0 C. for 24 h under argon. The resin was then filtered, washed (NMP; dichloromethane/methanol gradient) and dried to give the title compound (6.9 g) which was used directly in Description 41.
A solution of stannous chloride dihydrate (9 g) in N,N-dimethylformamide (DMP) (120 ml) was stirred for 72 h at room temperature under argon with the resin from Description 40 (6.9 g). The resin was filtered, washed (DMF; dichloromethane/methanol gradient) and dried to give the title compound (6.6 g) which was used directly in Description 42.
A solution of aryl sulfonyl chloride (0.4 mmol) and di-isopropylethylamine (1 mmol) in dichloromethane (3 ml) was agitated for 24 h at room temperature with the resin (0.1 mmol) from Description 41. The resin was then filtered, washed (dichloromethane; dichloromethane/methanol gradient; methanol) to yield the title compound which was used directly in Examples 133-137.
A solution of 2-methoxy-5-nitrophenol (5.58 g; 0.033 mol), (S)-1-methyl-2-hydroxymethylpyrrolidine (3.45 g; 0.03 mol) and triphenylphosphine (8.65 g; 0.033 mol) in dry THF (80 ml) was cooled to 50 and treated with DEAD (5.2 ml; 0.033 mol) over 15 min. The reaction mixture was allowed to stand at RT for 16 h, then evaporated in vacuo and partitioned 5% NaOH(aq)/Et2O. The organic phase was separated and extracted with 10% HCl(aq). The aqueous extract was washed with Et2O, basified with 40% NaOH(aq) and extracted with Et2O. The organic extracts were washed with H2O, dried over Na2SO4 and evaporated in vacuo to yield the title compound (D43) (6.79 g; 85%) MH+=267.
A solution of (S)-1-methyl-2-(2-methoxy-5-nitrophenoxy)pyrrolidine (D43) (6.79 g;0.0255 mol) in ethanol (200 ml) was hydrogenated in the presence of 5% Pd/C catalyst (0.5 g added as an aqueous slurry) at atmospheric pressure and RT for 16 hours. The catalyst was removed by filtration through kieselguhr and the filtrate evaporated in vacuo to yield the title compound (D44) (5.64 g; 93%) MH+=237.